Flow regulating valve



Bat. 19, 1944. w Y ETAL 2,365,371

FLOW REGULATING VALVE Filed May 25, 1943 INVENTORS Win/55.95:. Qum an? Kq/w: A: o/M/ RSTRfl/VGE sage through which it extends.

Patented Dec. 19, 1944 UNITED" STATES PATENT ormcs FLOW REGULATING VALVE William P. Yant, Murraysville, and John P. Strange, Wilkinsburg, Pa.,. assignorsfi to Mine Safety Appliances Company, Pittsburgh, Pa.,,a corporation of Pennsylvania ApplicationMay 25, 1943, SerialNo; 488 372 2 Claims.

This invention relates to pressure reducing system is used that gives considerable leverage on the valve closure member inorder to crack the valve, followed by an increase in the rate of movement: of the closure member to Wide open position. As soon as the valve is cracked the pressures on the opposite sides of the. closure member are substantially equalized so that it" requires but little force to open the valve further. The initial cracking of such a valve, however, presents a problem because if it requires much force to open it, the breathing resistance of the apparatus is increased to the discomfort of the user. The leverage system disclosed in the abovementioned patent materially decreases the breathing resistance, but the invention disclosed herein is a" still: further improvement in that it requires even less force to open the valve.

It is among the objects of this invention to provide an oxygen flow regulating valve for respirators which can be readily cracked by the appl cation of a very small force and in a simple manner.

In accordance with this invention a valvecasing is provided with a passage having a seat at its inlet and normally engaged by a closure member that is pressed tightly against" the seat bya high pressure fluid, such as oxygen used with a re.-. .irator. Means is provided for tilting this closure member on its seat before removing it completely therefrom, for it: requires less force to tilt the closure than to remove it from the seat all at once Th moment that the closure is tilted, its inner surface is exposed to the high pressure fluid which thereupon. aids in further unseating the closure so that little mechanical force is required to completely open it. In order to tilt the closure, it preferably is provided with a valve stem that is smaller than the valve pas- The free end of the stem is engaged by suitable valve-opening means that moves it sidewaysand inwardly of the passage 0 that the stem first tilts the closure member on its seat and then pushes it entirely off the seat. The valve-opening means preferably includes a diaphragm adapted to be flexed by the inhalation of the user, and a diaphragm- The'invention will be described in connecoperated leverthat engages the stem and pushes on it when the diaphragm is drawn inwardly.

The" preferred embodiment of the invention is illustrated in the accompanying drawing in which Fig. 1 isa plan view" with the diaphragm and outercase partly broken away; Fig; 2 is a section taken substantially on the line IIII of Fig. 1; and Fig. B'i's a fragmentarysection showing the valve closure member tilted on its seat as it starts to open.

Referring to the drawing, respirable air or oxygen at high pressure is passed through a twostage regulating devicecontrolled by pressure resp'onsive means illustrated" as a Sylphon l mounted on the outsideof a housing 2; is a flexible corrugated tube havingits inner and open to receive gas through an opening 3'in the housing wall in order to exert pressure on the closed outer end of thetube for'expanding the tube axially. Secured'to the outer endioi the tube: is a rod" 4" which. extendsbackr through the tube and has its oppositeen'd pivotally connected to theflout'er end of a valve-actuating lever 5 piv otally mounted at its opposite'end on a sidewall of the housing. This'lever' has a lateral projection' Bthat engages a normally'open high pressure valve T in an inlet 8adapted to be connected to the source ofoxygenat" high pressure. Thevalve 1- is closed by lever 5 when the Sylphon tubeis expanded by gas in the high pressure chamber 9 formed. in thehousing by 'thepartiti'on wall I 0.

To further reducethe'pressure of the oxygen for respiratory use, a lowpressure valve I2 is mounted in'an'opening' in partition W'that separates'the high pressure chamber'from a lowpressure chamber 13. One side of chamber I3 has an outlet M adapted to be connected to a face pi'e'ce worn by the user" of therespirator, or to any other type of breathin apparatus where the results of my improvedivalve can be utilized. The

low pressure valve I2-inc1udesa casing I6 threaded in the partition wall and provided with an enlarged passage. l T connecting the two cham bers. At the inlet end' of the passage in high pressure chamber 9 there is a valve seat l8 engaged by a disc-like closure member l9. Rigidly connected to the center of this member and extending from it through the-valve passage is a valve stem 2 The closure member is urged? toward the valve seat by a light coil spring" 22 encircling the stem and compressed between a collar 23 on the stem and a perforated wal1 24 within the passage.

The Sylphon:

The free end of the stem extends'through an opening- 25 in arectangular' plate 26 secured by screws 2T to a flange 28 enapplied by the diaphragm to the valve.

circling the outlet end of the valve casing. In

accordance with this invention, opening and the stem-receiving opening in wall E i are somewhat larger than the stem so that the stem can be tipped or canted in the valve passage for a purpose about to be described.

The side of the housings low pressure chamber 13 opposite valve i2 is formed by a flexible diaphragm 3i the edge or which is clamped to the circular wall of the chamber by a threaded ring 32 provided with a central opening 33. The low pressures involved in inhalation, and the limited area of the diaphragm, make the diaphragm itself incapable of opening valve 12 against the higher gas pressure in chamber 9, and some means therefore is required to magnify or increase the valve-opening force or pressure exerted by the diaphragm. This means preferably comprises a pair of levers pivoted at one end on opposite sides of the valve and projecting across thevalve stem 3. l

in opposite directions in overlapping relation. The inner lever 35 is pivoted to plate 26 at a point close to the end of the stem which itengages. The other lever 36 is pivoted at the opposite end of the plate and extends outwardly at an angle :i

toward the'center of the diaphragm in overlapping relation with the inner lever. The outer end of the outer lever carries a small roller 3? that engages a metal disc 38 attached to th central portion of the diaphragm. Near its inner end the outer lever is provided with a small roller 39 that bears against the adjacent end portion of the inner lever. It will be evident from this arrangement of levers that the diaphragm is enabled through them to exert considerable pressure on the valve stem in order to open the low pressure valve l2.

The outer ends of the two levers are connected by a coil spring 4! that tends to swing their free ends toward the diaphragm and to hold roller 3'! against disc 38. The spring also serves to lift the levers away from the valve when the regulator is in a position with the diaphragm and levers on the upper side and the valve closed. Without the spring the weight of the diaphragm and that of the levers would exert a force which, when it is magnified by the mechanical advantage of the levers, would be suflicient to prevent the valve stem from righting itself and complete- 1y closing the valve.

It is evident that the spring is useful only when the valve is in closed position or at the point of closing. A spring which tended to move the levers away from the stem at all times would also oppose the action of the diaphragm when the valve was in open position. This would create the need for a greater force exerted by the diaphragm and hence a greater suction produced by inhalation to keep the valve in the open position. The coil spring 4| is therefore attached to the two levers in such a way that the force tending to lift the levers is greatest when the valve is in the closed position and this force decreases as the levers assume new positions in the direction of the open position of the valve.

As the diaphragm is drawn inwardly b inhalation through outlet M, valve i2 is first cracked, which results in' the gas pressure on its opposite sides being substantially equalized. Less force then is required to open it to full open position. Because of this fact, there is no disadvantage in roller 39 moving toward the pivot of inner lever 35 and thereby decreasing the force On the lit contrary, there is an advantage in this movement of the inner roller because its movement along the inner lever shortens the efi'ective length of the lever arm and thereby increases the rate of movement of the closure to wide open position. Consequently, the valve is quickly opened. Also, the distance it travels and hence the available area for the passage of gas is greater than that which would result if the high mechanical advantage needed for the opening of the valve were maintained throughout the entire stroke.

It is a feature of this invention, although the lever system is similar to that disclosed in the above-mentioned patent, that less pressure on the end of the valve stem is required to open the valve. This is because the construction of the valve is such that the closure member [9 is tilted on its seat, as shown in Fig. 3, before it is completely removed from it, so that the cracking of the valve starts at'one point on the seat and proceeds in opposite directions around it rather than occurring all around the seat at once. In order to first tilt the closure in this manner, the inner lever 35 normally is inclined relative to the valve stem as shown in Fig. 2 so that as the free end of the lever is swung inwardly by roller 39 the stem-engaging point on the lever moves in an arc and thus swings the outer end of the stem in the general direction of the pivot of the outer lever 36. The canting of the stem may be very slight because it is only necessary that it be sufficient to tilt closure member [9 on its seat far enough to raise one side of the closure off the seat and thereby expose its inner or low pressure surface to the higher gas pressure in high pressure chamber 9. The gas pressure on the opposite faces of the closure member is never quite equalized, because when the pressure in chamber 9 drops, the Sylphon collapses and opens the high pressure valve 1, thus permitting a flow from the source into chamber 9. This flow tends to maintain a pressure in chamber 9 which insures a flow of gas through valve 18 and into the breathing tube. However, the pressure when the gas is flowing is always below the static pressure'due to the resistance of the system. This valve and lever system take advantage of this fact and change from the tilting motion to the straight pushing motion after the valve is cracked and so achieve a quicker opening and greater area when open.

It will be evident that it requires less force to tilt the closure member than to move it straight oiT its seat all at once, but the valve is opened as quickly in one case as the other. Of great importance is the fact that by first tilting the closure on its seat, the breathing resistance of the device is decreased.

According to the provisions of the patent statutes, we have explained the principle and construction of our invention and have illustrated and described what we now consider to represent its best embodiment. However, we desire to have it understood that, Within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

We claim:

1. An oxygen flow regulating valve for respirators, comprising a valve casing provided with a passage having a seat at its inlet end, a closure member normally engaging said seat, a stem rigidly connected to said closure and extending through said passage, said stem being smaller than said passage whereby it can be canted in the passage, a lever pivoted at one side of the stem and extending across its free end at an inclination thereto, an outer lever pivoted at the opposite side of the stem and overlapping the first lever with the free end of the latter operatively connected to the outer lever at a point close to the pivot of the outer lever, whereby movement of the outer lever towards the passage causes the first lever to tip the stem and push it inwardly of the passage to tilt the valve 010 sure on its seat before pushing it completely off the seat, and a spring connecting the free ends of said levers for biasing them away from said stem.

2. An oxygen flow regulating valve for respirators, comprising a valve casing provided with a passage having a seat at its inlet end, a closure member normally engaging said seat, a stem rigidly connected to said closure and extending through said passage, said stem being smaller than said passage whereby it can be canted in the passage, a lever pivoted at one side of the stem and extending across its free end at an inclination thereto, an outer lever pivoted at the opposite side of the stem and overlapping the first lever with the free end of the latter operatively connected to the outer lever at a point close to the pivot of the outer lever, whereby movement of the outer lever towards the passage causes the first lever to tip the stem and push it inwardly of the passage to tilt the valve closure on its seat before pushing it completely ofi the seat, and a spring connecting the free ends of said levers for biasing them away from said stem, the inclination of said levers to each other being such that said biasing action of the spring is negligible except when the levers are in their outermost positions.

WILLIAM P. YANT.

JOHN P. STRANGE. 

